Around the world, nowadays, the methods of utilizing the vanadium-titanium-iron concentrate are as below. (1) The process of blast furnace-converter can only extract the iron and a part of vanadium, while the titanium enters the blast furnace slag and cannot be effectively and economically recovered and utilized. A large amount of blast furnace titanium slag that is additionally produced causes a huge drain of titanium resources and serious environmental pollution. (2) In the process of rotary hearth furnace-electrical furnace, the vanadium-bearing titano-magnetite is firstly pre-reduced in a rotary hearth furnace, and then is melted and separated by the electrical furnace, such that hot metal and the titanium enriched slag are obtained. However, the location of vanadium is hard to control, and the utilization rate of the vanadium is not high. Also, the mineral phase of the melting-separated titanium slag is stable, and has a compact structure. There is no mature process to deal with melting-separated titanium slag at present. Only a small amount of melting-separated titanium slag is used as a raw material to produce titanium dioxide pigment in sulfate process. (3) The process of direct reduction and grinding beneficiation achieves the separation of iron and vanadium-titanium, and obtains iron powder and vanadium-titanium enriched slag. The vanadium-titanium enriched slag is further subjected to the process of sodium salt roasting. The vanadium is extracted by water leaching. The vanadium solution and the titanium enriched slag are obtained. (4) In the process which firstly extracts the vanadium, the vanadium-titanium-iron concentrate firstly is subjected to the process of sodium salt roasting and water leaching extraction of vanadium. Next, the iron making process with the blast furnace or the non-blast furnace is conducted. After the vanadium extraction, since the content of residual sodium is high, the smooth conduction of the process of iron making is negatively affected. Also, the obtained titanium slag still cannot be utilized as in above processes. Moreover, these processes require conducting two or three high-temperature steps to achieve the effective separation of the iron, the vanadium, and the titanium. There are defects of a long process, a high investment, a high cost, serious pollution, and a low comprehensive utilization degree. In view of the above, no matter what kind of usage is conducted, the recovering and utilization of the iron, the vanadium, and the titanium from the vanadium-bearing titano-magnetite cannot be achieved simultaneously, which causes a waste of resources. The present invention provides a new method for converting and separating the vanadium, the titanium, and the iron from the vanadium-titanium-iron concentrate in one step. An efficient and clean recovery of the vanadium, the titanium, and the iron is achieved. The method has the significant advantages of the short process, low investment, low production cost, reduced environmental pollution, the efficiency of comprehensive recovery, and has a wide application prospect.